Zubimendi bagged his first goals for the Gunners following his close-season move from Real Sociedad.

The Spain midfielder opened the scoring in the first half and netted again in the closing stages after Viktor Gyokeres doubled Arsenal's lead soon after the break.

Arsenal's third win in four games took them to the top of the table on goal difference ahead of Liverpool, who face Burnley on Sunday.

A 1-0 defeat against champions Liverpool in their last match before the international break had punctured the optimism at Arsenal after successive wins against Leeds and Manchester United to start the season.

But this was the kind of confident display, highlighted by Noni Madueke's virtuoso performance, that Gunners boss Mikel Arteta believes will keep his side in contention to win the title.

The only dark cloud for Arteta was an injury to Arsenal captain Martin Odegaard, who was forced off in the first half with what looked like a shoulder problem.

Odegaard joins a lengthy injury list that already includes Bukayo Saka, Kai Havertz, Gabriel Jesus and William Saliba.

It was a frustrating return to north London for Postecoglou, just three months after he was unceremoniously sacked by Tottenham despite winning the Europa League last season to end the club's 17-year trophy drought.

Postecoglou was hired by Forest this week following Nuno Espirito Santo's dismissal after his relationship with owner Evangelos Marinakis collapsed.

Marinakis immediately piled pressure on Postecoglou, who presided over Tottenham's worst top-flight finish since 1976-77 last season, by claiming Forest were in a position to challenge for major trophies.

However, the Australian didn't win a north London derby as Tottenham boss and was unable to guide Forest to their first victory on Arsenal turf since 1989.

- Clinical Arsenal -

Arsenal's Eberechi Eze made his first start since signing from Crystal Palace in August, while the winger's England team-mate Declan Rice was left on the bench.

Arteta was criticised for using three 'defensive' midfielders in the loss at Liverpool, but Mikel Merino scored a hat-trick for Spain during the international break and he should have put Arsenal ahead in the opening stages.

Merino pounced on the loose ball when a free-kick dropped to him, but Forest keeper Matz Sels repelled his close-range effort.

Odegaard tried to play on after an awkward fall but the Norway midfielder was eventually by Ethan Nwaneri with just 18 minutes gone.

Arsenal's set-piece excellence had tormented Postecoglou during his time at Tottenham and it nearly paid off again when Jurrien Timber's glancing header flashed just wide from Noni Madueke's corner.

It was no surprise when Arsenal took the lead from another dead-ball delivery in the 32nd minute, but Zubimendi's strike was far from routine.

Meeting the ball on the volley, he blasted a brilliant strike from the edge of the area that took a slight deflection off Forest defender Murillo as it flashed past Sels.

Gyokeres put Arsenal in complete control just 46 seconds after the interval.

It was a goal that showcased Arteta's summer recruitment as Eze whipped in a low cross for Gyokeres to slot home with ease for third goal since arriving from Sporting Lisbon.

Forest almost hauled one back immediately as Wood's flick cannoned off the bar.

Gyokeres nearly wrapped up the points with a drive against the post after Eze and Madueke combined to carve through the creaky Forest defence.

Zubimendi administered the knockout blow in the 79th minute, rising to meet Leandro Trossard's cross with a clinical header.